Resonance Mechanism Research Articles

Nonlinear superposition between lump soliton and other nonlinear localized waves for the (2+1)-dimensional Korteweg–de Vries–Sawada–Kotera–Ramani equation

In the previous studies, the authors have reported the lump soliton collided with other nonlinear localized waves for (2+1)-dimensional Korteweg–de Vries–Sawada-Kotera–Ramani equation. However, this work will introduce a novel restrictive condition to reveal the nonlinear superposition between a lump soliton and other nonlinear localized waves. Under the premise of the acquired N-soliton solutions, the nonlinear superposition structures among lump soliton, stripe solitons, resonance Y-type solitons and breather waves guarantee that the lump soliton does not collide with other localized waves by means of the long wave limit approach, soliton resonance method and symbolic computation. Meanwhile, a variety of soliton molecules are yielded through nonlinear superposition and velocity resonance mechanisms. The obtained solutions in this work will bring about new perception of the interaction behavior between lump soliton and other nonlinear localized waves, and provide more brand new insights into the nonlinear phenomena triggered by the areas of plasma physics, fluid dynamics and nonlinear optics.

Research on the Vibration Reduction Design of Camshaft Swing Grinding Based on Local Resonance Mechanism

Research on the Vibration Reduction Design of Camshaft Swing Grinding Based on Local Resonance Mechanism

Double Fano sensing mechanism of waveguide coupled surface plasma

Based on the optical properties of waveguide-coupled surface plasmon resonance, a sensor of surface plasmon coupled waveguide resonance with double discrete states generated by the upper and lower waveguide structures combined with prisms and Au films, respectively, is proposed. In this paper, the sensing structure is studied numerically and analytically, and the transmission characteristics of surface equipartition excitations are analyzed and elaborated in-depth in combination with the reflection angle spectrum, as well as the generation and evolution mechanism of dual Fano resonance at different incidence angles at fixed wavelengths. The structural model of Fano resonance sensing based on angle modulation is established, and the sensing characteristics are analyzed to produce electromagnetic field enhancement at low-angle Fano. The mathematical model between structural parameters and spectral performance is established using back propagation (BP) neural network, and the particle swarm optimization (PSO) algorithm is used to find the input structural parameters corresponding to the optimal performance, The results show that the quality factor of resonance (FOM) and sensitivity is significantly improved; When it is used in the field of biosensing, the response curves of Fano with different angles of high and low to concentration are quite different, thus realizing high precision detection of different concentrations of solutions and reflecting excellent sensing performance.

Origin of the anomalous spin resonance in a strongly correlated electron system

We study the origin of the anomalous spin resonance detected electrically in a strongly correlated two-dimensional electron system. Such resonance reveals itself around nominally nonmagnetic even filling factors $\ensuremath{\nu}$ of the integer quantum Hall effect and is a consequence of strong electron-electron interactions. We directly demonstrate that while the spin resonance at odd $\ensuremath{\nu}$ manifests itself as an increase in the longitudinal resistance of the two-dimensional channel induced by the usual heating due to the radiation absorption, the anomalous resonance around even fillings is detected as a drop in the resistance, as if the electron system is cooled. In contrast, if the magnetic field is tilted so that the ground state of the system becomes ferromagnetic at even $\ensuremath{\nu}$, the spin resonance around even fillings turns to a more conventional ``heating''-like behavior. Analysis of both the evolution of the spin resonance with increasing tilt angle and the measured temperature dependencies allowed us to put forth a possible mechanism of anomalous spin resonance around even fillings that qualitatively explains all of the puzzling experimental findings.

Stochastic versus dynamic resonant activation to enhance threshold detector sensitivity

The Josephson junction, as a threshold detector, is studied in the presence of noise and a weak external signal in the framework of the pendulum model. A range of parameters, efficient for weak signal detection has been found. While in the low noise limit the signal can be enhanced via dynamic resonant activation mechanism, even weaker signals can be efficiently detected with the help of noise via stochastic resonant activation mechanism. The parameter optimizations of a microwave single photon counter prototype based on aluminum Josephson junction are discussed.

Triphenylamine‐ and triazine‐based conjugated microporous polymers constructing from triphenylamine and its derivatives with nitrogen as core for fluorescence sensing o‐nitrophenol

AbstractThree triphenylamine‐ and s‐triazine‐based conjugated microporous polymers (TTPA, TTDATA, and TTMDATA) were prepared via the Friedel−Crafts arylation reactions under the catalytic action of CH3SO3H. In virtue of containing rich nitrogen atoms in their porous frameworks, the obtained TTPA, TTDATA, and TTMDATA possess good fluorescence sensing property for o‐nitrophenol (o‐NP) with high quenching coefficients of 1.54 × 104, 1.32 × 104, 1.33 × 103 L mol−1 and low limits of detection (LODs) of 2.44 × 10−9, 1.14 × 10−11, and 1.35 × 10−8 mol L−1, respectively. The fluorescent quenching mechanism of TTPA for selective sensing o‐NP is the photo‐induced charge‐transfer mechanism. However, the fluorescent quenching mechanisms of TTDATA and TTMDATA for selective sensing o‐NP have both the photo‐induced charge‐transfer mechanism and the resonant energy transfer mechanism.

Research on Reradiation Interference Resonance Mechanism of Power Transmission Lines in Medium-Wave Band Based on Characteristic Mode Theory

The key to decreasing reradiation interference (RRI) of power transmission lines on adjacent radio stations is to clarify the RRI resonance mechanism. Aiming at the defects of existing RRI resonance analysis methods, including frequency limitation and lack of physical explanation, a RRI resonance analysis method based on characteristic mode (CM) theory is proposed in this paper. Firstly, based on the generalized eigenvalue equation, a set of characteristic currents with orthogonal relationship and their eigenvalues for power transmission lines are solved, and combined with Poynting’s theorem, the CM radiation characteristics are analyzed. Secondly, under specific external excitation, CM-related parameters are obtained through modal decomposition. Finally, the total energy radiated by power transmission lines is decomposed into the superposition of energy radiated by each CM, and the mechanism of RRI resonance is clarified from the perspective of CM. The simulation results show that compared with the IEEE guide and the generalized resonance theory, the method in this paper is effective and independent of observation points, which can provide a theoretical support for further research on the RRI suppression measures.

Numerical modelling of resonance mechanisms in jointed rocks using transfer functions

Resonance effects in parallel jointed rocks subject to stress waves are investigated using transfer functions, derived from signals generated through numerical modelling. Resonance is important for a range of engineering situations as it identifies the frequency of waves which will be favourably transmitted. Two different numerical methods are used for this study, adopting the finite difference method and the combined discrete element-finite difference method. The numerical models are validated by replicating results from previous studies. The two methods are found to behave similarly and show the same resonance effects; one operating at low frequency and the other operating at relatively high frequency. These resonance effects are interpreted in terms of simple physical systems and analytical equations are derived to predict the resonant frequencies of complex rock masses. Low frequency resonance is shown to be generated by a system synonymous with masses between springs, described as spring resonance, with an equal number of resonant frequencies as the number of blocks. High frequency resonance is generated through superposition of multiple reflected waves developing standing waves within intact blocks, described as superposition resonance. While resonance through superposition has previously been identified, resonance based on masses between springs has not been previously identified in jointed rocks. The findings of this study have implications for future analysis of multiple jointed rock masses, showing that a wave travelling through such materials can induce other modes of propagation of waves, i.e. spring resonance.

Multilayer coupled plate-type acoustic metamaterials for low-frequency broadband sound insulation

Acoustic metamaterials have been becoming a popular topic for the better sound insulation at low frequency than traditional materials. However, due to the local resonance mechanism, this excellent performance can only be demonstrated in narrow frequency bands. Therefore, multilayer coupled plate-type acoustic metamaterials (MPAM) are proposed in this paper. The structure consists of a large plate-type acoustic metamaterial (PAM) with periodic square metamaterial units and double-layer fibers with different densities. According to finite element study on the insertion loss (IL) of the MPAM, the governing physical mechanism of the MPAM was analyzed according to the sound pressure level distributions and the vibration modes of the PAM layer. In addition, large-scale MPAM samples with a size of 506 mm*506 mm were manufactured, the reverberation and anechoic chamber was employed to verify the sound insulation performance. It can be concluded from the test results that the IL peak originate from the anti-resonance of the PAM layer rather than the weight of the materials. Compared to the structures without PAM layer, in the range of 360 Hz−950 Hz, the IL is increased by 5 dB at least and up to 17 dB at most. The influences of the incident angles, the frame density and the coverage rate of the PAM layer on the IL are disscussed. The proposed MPAM structure, analytical techniques and test results may be helpful for the engineering application of acoustic metamaterials.

Simultaneous Detection of Tumor Derived Exosomal Protein-MicroRNA Pairs with an Exo-PROS Biosensor for Cancer Diagnosis.

Tumor derived exosomes (TEXs) have emerged as promising biomarkers for cancer liquid biopsy. Conventional methods (such as ELISA and qRT-PCR) and emerging biosensing technologies mainly detect a single type of exosomal biomarker due to the distinct properties of different biomolecules. Sensitive detection of two different types of TEX biomarkers, i.e., protein and microRNA combined biomarkers, may greatly improve cancer diagnostic accuracy. We developed an exosome protein microRNA one-stop (Exo-PROS) biosensor that not only selectively captured TEXs but also enabled in situ, simultaneous detection of TEX protein-microRNA pairs via a surface plasmon resonance mechanism. Exo-PROS assay is a fast, reliable, low sample consumption, and user-friendly test. With a total of 175 cancer patients and normal controls, we demonstrated that TEX protein-microRNA pairs measured by Exo-PROS assay detected lung cancer and breast cancer with 99% and 96% accuracy, respectively. Exo-PROS assay also showed superior diagnostic performance to conventional ELISA and qRT-PCR methods. Our results demonstrated that Exo-PROS assay is a potent liquid biopsy assay for cancer diagnosis.

Tunable resonant absorption emanating from in-plane hyperbolic phonon polaritons

Resonances play a key role in the practical application of polaritons because they can be easily detected from the far field and integrated with various devices. Although the mechanism and implementation of polariton resonances have been studied extensively, the resonant behaviors of in-plane anisotropic polaritons and their tuning strategies remain largely unexplored so far. Here, using in-plane hyperbolic phonon polaritons in α-MoO3 as an example, we analyze their resonant absorption upon multiple conditions theoretically. We unveil the collective resonant mode originating from synergistic Fabry−Pérot cavity resonances and Bragg resonances. Beyond controlling polarizations and geometries, active tuning of resonant absorption is further achieved by rotating resonators or changing polariton topologies. Our results bridge the gap between polariton dispersions and resonant absorption, and provide a bottom-up strategy for the design of polariton-based resonators, photonic crystals, and metasurfaces. The resonant structures proposed here could serve as versatile building blocks for infrared absorbers, polarization detectors, sensors, modulators, and other photonic devices.

Resonant Mechanism for a Long-Distance Wireless Power Transfer Using Class E PA and GaN HEMT

This paper presents a study on long-distance wireless power transfer (WPT), which formulates the voltage gain in terms of the coupling coefficient between the power transmitting unit (PTU) and the power receiving unit (PRU) coils. It is proposed that maximum power transfer efficiency (PTE) can be reached when maximum voltage gain is achieved under a matching condition between the coil quality factor and the coupling coefficient. In order to achieve maximum power delivered to load (PDL), we need to elevate the input voltage as high as the high breakdown-voltage of gallium nitride (GaN) high-electron mobility transistors (HEMT) along with class E amplifier circuit topology. In order to promote voltage gain, knowledge of the coupling coefficient between two coils including the factors of the coil diameter, wire diameter, coil turns, and the coil resistance are derived. It was observed that a lower coil resistance leads to a reduced parallel quality, which facilitates long-distance wireless power transfer. Experimental results support the findings that the maximum PTE occurred at the maximum voltage gain existing at a specific distance matches the coupling coefficient between coils. A maximum power point tracking (MPPT) method is also developed to achieve maximum PDL. At a distance of 35 cm, experiments with more than 100 W successfully receive a PTE of 57% at the PRU when the received voltage reached 1.4 kV. This is used to verify the concepts and analysis that are proposed in this paper.

Revisiting Reentry Roll Resonance

This paper revisits the subject of reentry roll resonance, which occurs when the roll rate and pitch frequency become equal in a spinning reentry vehicle. A first-principles model is developed and analyzed numerically and by using a reduced-order pendulum model for the relative phase of the roll and pitch/yaw axes. The results show good qualitative agreement with recent flight data and provide a natural physical interpretation. Based on the model it is suggested that sustained roll resonance depends primarily on the initial phase relationship between the pitch and roll axes, in addition to the vehicle moments of inertia and the vehicle symmetry. Finally the model is used to propose a mechanism for sustained resonance in vehicles spinning about a major axis, a condition previously thought to be forbidden.

Frequency-domain-resolved investigation of unitary h-shaped pulses.

We experimentally investigate the generation of h-shaped pulse in an all-polarization-maintaining (PM) and all-normal-dispersion (ANDi) mode-locked fiber laser. The generated pulse is demonstrated to be a unitary pulse, instead of a noise-like pulse (NLP). Furthermore, by employing an external filtering system, the obtained h-shaped pulse can be resolved into rectangular-shaped pulses, chair-like pulses, and Gaussian pulses. The authentic AC traces with a double-scale structure of unitary h-shaped pulses and chair-like pulses are observed on the autocorrelator. The chirp of h-shaped pulses is also proved similar to that of DSR pulses. To the best of our knowledge, this is the first time that the existence of unitary h-shaped pulse generation has been confirmed. Moreover, our experimental results reveal the close relationship of formation mechanisms of dissipative soliton resonance (DSR) pulses, h-shaped pulses, and chair-like pulses, which helps to unify the essences of such "DSR-like" pulses.

Stability of internal gravity wave modes: from triad resonance to broadband instability

A theoretical study is made of the stability of propagating internal gravity wave modes along a horizontal stratified fluid layer bounded by rigid walls. The analysis is based on the Floquet eigenvalue problem for infinitesimal perturbations to a wave mode of small amplitude. The appropriate instability mechanism hinges on how the perturbation spatial scale relative to the basic-state wavelength, controlled by a parameter $\mu$ , compares to the basic-state amplitude parameter, $\epsilon \ll 1$ . For $\mu ={O}(1)$ , the onset of instability arises due to perturbations that form resonant triads with the underlying wave mode. For short-scale perturbations such that $\mu \ll 1$ but $\alpha =\mu /\epsilon \gg 1$ , this triad resonance instability reduces to the familiar parametric subharmonic instability (PSI), where triads comprise fine-scale perturbations with half the basic-wave frequency. However, as $\mu$ is further decreased holding $\epsilon$ fixed, higher-frequency perturbations than these two subharmonics come into play, and when $\alpha ={O}(1)$ Floquet modes feature broadband spectrum. This broadening phenomenon is a manifestation of the advection of small-scale perturbations by the basic-wave velocity field. By working with a set of ‘streamline coordinates’ in the frame of the basic wave, this advection can be ‘factored out’. Importantly, when $\alpha ={O}(1)$ PSI is replaced by a novel, multi-mode resonance mechanism which has a stabilising effect that provides an inviscid short-scale cut-off to PSI. The theoretical predictions are supported by numerical results from solving the Floquet eigenvalue problem for a mode-1 basic state.

Efficient Meta-couplers Squeezing Propagating Light into On-Chip Subwavelength Devices in a Controllable Way

On-chip photonic systems play crucial roles in nanoscience and nanoapplications, but coupling external light to these subwavelength devices is challenging due to a large mode mismatch. Here, we establish a new scheme for realizing highly miniaturized couplers for efficiently exciting on-chip photonic devices in a controllable way. Relying on both resonant and Pancharatnam-Berry mechanisms, our meta-device can couple circularly polarized light to a surface plasmon, which is then focused into a spot placed with a target on-chip device. We experimentally demonstrate two meta-couplers. The first can excite an on-chip waveguide (with a 0.1λ × 0.2λ cross section) with an absolute efficiency of 51%, while the second can achieve incident spin-selective excitation of a dual-waveguide system. Background-free excitation of a gap-plasmon nanocavity with the local field enhanced by >1000 times is numerically demonstrated. Such a scheme connects efficiently propagating light in free space and localized fields in on-chip devices, being highly favored in many integration-optics applications.

The internal transport barrier formation on EAST tokamak during the fishbone instability

The internal transport barrier (ITB) which is related to the fishbone instability has been observed on the Experimental Advanced Superconducting Tokamak (EAST) in ELMy H-mode discharges. An interpretation of the formation of the ITB on EAST tokamak is provided, based on both analytical and numerical calculations. The fishbone instability induces the redistribution of fast ions and leads to the accumulation of fast ions in a local region where the ITB is going to appear. Correspondingly, the gradients of fast ions are enhanced, where the ion temperature gradient (ITG) mode exists. Fast ions can interact with the ITG mode through the dilution, Shafranov shift and wave-particle resonance mechanisms. It is found that the ITG mode is stabilized by fast ions and the stabilizing effects are determined mainly by the density, temperature and their gradients of fast ions. The enhanced density and temperature gradients of fast ions lead to a stronger stabilizing effect on ITG mode. Compared with the stabilizing effect before the appearance of fishbone instability, the stabilization on ITG mode is enhanced after the fishbone instability, which is beneficial to the formation of the ITB.

Vibration and Bandgap Behavior of Sandwich Pyramid Lattice Core Plate with Resonant Rings

The vibration suppression performance of the pyramid lattice core sandwich plates is receiving increasing attention and needs further investigation for technical upgrading of potential engineering applications. Inspired by the localized resonant mechanism of the acoustic metamaterials and considering the integrity of the lattice sandwich plate, we reshaped a sandwich pyramid lattice core with resonant rings (SPLCRR). Finite element (FE) models are built up for the calculations of the dispersion curves and vibration transmission. The validity of the bandgap of the SPLCRR and remarkable vibration suppression are verified by experimental observations and the numerical methods. Furthermore, the effects of geometric parameters, material parameters and period parameters on the bandgaps of the SPLCRR are systematically investigated, which offers a deeper understanding of the underlying mechanism of bandgap and helps the SPLCRR structure meet the technological update requirements of practical engineering design.

Seismic metamaterials based on coupling mechanism of inertial amplification and local resonance

Inertial amplification mechanisms could be used to control the propagation of elastic waves in beams and slabs, but it was a difficult problem to apply inertial amplification mechanisms to seismic metamaterials to design low-frequency broadband. This paper presents a inertially amplified locally resonant seismic metamaterial (IALR-SM) using the coupling mechanism of inertial amplification and local resonance. In contrast to the locally resonant seismic metamaterial (LRSM), the large-mass columns as local resonators of IALR-SM are attached to the connector and small-mass columns to form the inertia amplification structures. The finite element method calculates the eigenmodes’ band structure and displacement vector field. Numerical results indicated that the bandwidth of the IALR-SM increases by 194% compared to LRSM for seismic surface waves below 20 Hz. The formation mechanism of the yield in large band gaps is attributed to the coupling mechanism of local resonance and inertial amplification. In addition, the numerical effects of geometric parameters on the band gaps are investigated. The findings showed that the side length of the small-mass columns plays a vital role in determining which coupling mechanism is dominant. Finally, field experiments demonstrated that the IALR-SM generates low-frequency broadband.

Resonant mechanisms that produce near-Sun asteroids

ABSTRACT All near-Earth asteroids (NEAs) that reach sufficiently small perihelion distances will undergo a so-called super-catastrophic disruption. The mechanisms causing such disruptions are currently unknown or, at least, undetermined. To help guide theoretical and experimental work to understand the disruption mechanism, we use numerical simulations of a synthetic NEA population to identify the resonant mechanisms that are responsible for driving NEAs close to the Sun, determine how these different mechanisms relate to their dynamical lifetimes at small heliocentric distances and calculate the average time they spend at different heliocentric distances. Typically, resonances between NEAs and the terrestrial and giant planets are able to dramatically reduce the perihelion distances of the former. We developed an algorithm that scans the orbital evolution of asteroids and automatically identifies occurrences of mean motion and secular resonances. We find that most near-Sun asteroids are pushed to small perihelion distances by the 3:1J and 4:1J mean-motion resonances with Jupiter, as well as the secular resonances ν6, ν5, ν3, and ν4. The time-scale of the small-perihelion evolution is fastest for the 4:1J, followed by the 3:1J, whereas ν5 is the slowest. Approximately 7 per cent of the test asteroids were not trapped in a resonance during the latest stages of their dynamical evolution, which suggests that the secular oscillation of the eccentricity due to the Kozai mechanism, a planetary close encounter, or a resonance that we have not identified pushed them below the estimated average disruption distance.